A fluorinated monomer such as a perfluoro(alkyl vinyl ether) is useful as a starting material monomer for a fluorinated resin which is excellent in heat resistance and chemical resistance. For example, a perfluoro(alkyl vinyl ether) having a carboxy group in its molecule is useful as a starting material monomer for an ion exchange membrane and is produced via a diacyl fluoride (Non-Patent Document 1).
As the process for producing a diacyl fluoride used for producing a fluorinated monomer, a process having the following steps (1) to (3) has been known (Patent Document 1).
Step (1): A step of reacting a bifunctional alcohol with a monoacyl fluoride to obtain a partially fluorinated ester.
Step (2): A step of obtaining a perfluoroester from the partially fluorinated ester by a fluorination reaction.
Step (3): A step of obtaining a diacyl fluoride by a decomposition reaction of the perfluoroester.